CN111734655B

CN111734655B - Turbofan for breathing machine

Info

Publication number: CN111734655B
Application number: CN202010754900.0A
Authority: CN
Inventors: 张龙飞; 孙杰; 王永红; 李国斌
Original assignee: Vofon Turbo Systems Ningbo Co ltd
Current assignee: Ningbo Fengwo booster Technology Co.,Ltd.
Priority date: 2020-07-31
Filing date: 2020-07-31
Publication date: 2020-12-29
Anticipated expiration: 2040-07-31
Also published as: CN111734655A

Abstract

The invention discloses a turbofan for a respirator, which helps the turbofan for the respirator to improve efficiency, reduce current and rotating speed requirements, further reduce heat generation and improve system reliability, and comprises a brushless coreless motor, a volute and an impeller arranged in the volute, wherein the volute comprises an upper shell and a lower shell, the upper shell is provided with an air inlet, a flow channel is arranged in the volute along the circumferential direction, the upper shell and the lower shell are matched with an annular straight air channel positioned between the flow channel and the outer edge of the impeller, the annular straight air channel is communicated with the flow channel, the impeller comprises an upper cover, the inner wall of the upper shell and the outer wall of the upper cover are matched to form an air passing channel, the inner wall of the upper shell is provided with at least one annular groove relative to the upper cover, and the annular groove is annular by taking the rotating center of the impeller as the center of a circle, so that the improvement of the system efficiency is facilitated.

Description

Turbofan for breathing machine

Technical Field

The invention relates to the technical field of medical equipment manufacturing, and discloses a turbofan for a respirator, which is provided with structural designs with a plurality of characteristics, including structural designs of notches, runners, inlet characteristics and the like, and is used for helping the turbofan for the respirator and improving the compression efficiency.

Background

In modern clinical medicine, a ventilator has been widely used in respiratory failure due to various reasons, anesthesia and breathing management during major surgery, respiratory support therapy and emergency resuscitation as an effective means for manually replacing the function of spontaneous ventilation, and has a very important position in the modern medical field. The breathing machine is a vital medical device which can prevent and treat respiratory failure, reduce complications and save and prolong the life of a patient.

The turbo fan is an important accessory in the respirator, the turbo fan provides compressed air capable of controlling pressure and flow rate to obtain mixed gas with required oxygen concentration and flow for treatment, the turbo fan comprises a volute and an impeller arranged in the volute, the impeller is driven by a slotless and brushless hollow cup motor with low inertia, high rotating speed and low torque fluctuation, an air inlet is arranged in the center of one side of the volute, a flow channel is arranged along the circumference of the volute, the gas is sucked by an inlet under the action of a high-speed rotating impeller driven by the hollow cup motor, the gas obtains kinetic energy and internal energy through the work of the impeller, is further converted into required high-pressure gas through the flow channel, and finally is connected into equipment through an outlet.

In recent years, the working condition of the breathing machine becomes wide, and the volume of the breathing machine becomes smaller and smaller. The requirements on the pressure and the flow of the turbine fan are higher and higher, and the volume is strictly limited. The coreless motor has to be handled with increased rotational speed and increased current. Thereby causing adverse effects such as high heat generation and reduced reliability. In order to avoid adverse effects such as high heat generation and low reliability, the efficiency of the turbine fan is urgently needed to be improved by improving the efficiency of the turbine fan, so that the requirements on current and rotating speed are reduced.

Disclosure of Invention

The invention aims to provide a turbofan for a respirator, which helps the turbofan for the respirator to improve efficiency, reduce current and rotating speed requirements, further reduce heat generation and improve system reliability.

The technical scheme includes that the turbofan for the respirator comprises a brushless coreless motor, a volute and an impeller arranged in the volute, the volute comprises an upper shell and a lower shell, an air inlet is formed in the upper shell, a flow channel is formed in the volute along the circumferential direction, an annular straight air channel is arranged between the flow channel and the outer edge of the impeller in a matched mode between the upper shell and the lower shell, the annular straight air channel is communicated with the flow channel, the impeller comprises an upper cover, the inner wall of the upper shell is matched with the outer wall of the upper cover to form an air passing channel, at least one annular groove is formed in the inner wall of the upper shell relative to the upper cover, and the annular groove is annular by taking the rotation center of the impeller as the center of a circle.

Preferably, the section of the annular groove is square or arc.

Preferably, the inner wall of the upper shell and the outer wall of the upper cover are arranged in parallel, and the distance between the inner wall of the upper shell 11 and the outer wall of the upper cover 21 is 0.5-1.5mm

Preferably, the depth of the annular groove is 1/3-2/3 wall thickness, and the opening of the annular groove is 1-3 mm.

Preferably, the annular grooves are uniformly distributed in the air passing channel.

Preferably, the inner wall of the upper shell extends to form an extension section, the extension section is opposite to the inner wall of the upper cover, the extension section and the inner wall of the upper cover are matched to form an intersection air duct communicated with the air passing duct, and the axial length of the intersection air duct is 1-4 mm.

Preferably, the upper shell inner wall and the extension section are matched to form a flow resistance groove.

Preferably, the inner walls of the outer end part of the upper shell and the outer end part of the lower shell are respectively provided with an arc-shaped surface for forming a flow channel, the upper shell and the lower shell are respectively provided with an annular surface connected with the arc-shaped surfaces, and the annular surface on the upper shell and the annular surface on the lower shell form an annular straight air channel.

Preferably, the tail end of the flow channel is provided with an air outlet, and the cross section area of the flow channel along the airflow direction is linearly increased

Preferably, the air inlet is in a horn shape with the opening area gradually reduced along the air inlet direction, and the minimum section of the air inlet is larger than the maximum section of the air outlet.

After adopting the structure, compared with the prior art, the turbofan for the respirator has the following advantages: the method comprises the steps that an upper cover is arranged at first, an air passage is formed by matching the inner wall of an upper shell and the outer wall of the upper cover, the width of the air passage is 0.5-1.5mm, the air passage is too large, and high-pressure gas at an outlet of an impeller is easy to leak to a low-pressure area of an inlet, so that energy loss is caused. The air passage is too small, which easily causes interference and the risk of shell wiping. Through set up the cyclic annular wind channel of a plurality of square or arc on last casing, the high-pressure gas in impeller exit need enter these square or arc wind channels, just can reach the low pressure import district, very big increase the circulation resistance, blocked the possibility that high-pressure gas flows to the low pressure import district, avoided energy loss, improved system efficiency. The straight-line annular straight air channel is beneficial to reducing the air flow rate, better converts the dynamic pressure of air into static pressure, improves the pressure at the outlet of the flow channel and reduces the loss of the air in the flow channel. The design of the flow channel with linear gradual change is beneficial to the uniform flow of gas in the flow channel, reduces the loss and improves the system efficiency. The inlet design with gradually changed cross section is favorable for improving the uniformity of air inlet and the air inlet efficiency. The minimum cross section of the inlet is larger than the maximum cross section of the outlet, so that the gas flow is more smooth, and the system efficiency is improved.

Drawings

Fig. 1 is a first schematic structural diagram of a turbofan for a ventilator according to the present invention.

Fig. 2 is a schematic structural diagram of a turbofan for a ventilator according to the present invention.

Fig. 3 is a schematic cross-sectional view taken along a-a in fig. 2.

Fig. 4 is an enlarged view of fig. 3 at B.

Fig. 5 is a schematic structural view of the upper case of the present invention.

Fig. 6 is a schematic structural view of the flow channel of the present invention.

Shown in the figure: 1. a volute; 11. an upper housing; 12. a lower housing; 13. an air inlet; 14. a flow channel; 15. an extension section; 16. an annular straight air duct; 17. an air outlet; 18. a flow resistance slot; 19. an annular face; 2. an impeller; 21. an upper cover; 22. an impeller body; 23. an insert; 3. an air passage; 4. an annular groove; 5. an intersection air duct; 6. a brushless coreless motor; 7. and an air seal plate.

Detailed Description

The invention is further described with reference to the following figures and specific examples.

FIG. 1 and FIG. 2 are schematic structural diagrams of a turbofan for a respirator, FIG. 3 is a schematic sectional diagram of the turbofan for the respirator, the turbofan for the respirator includes a volute 1 and an impeller 2 disposed in the volute 1, the impeller 2 is driven by a brushless coreless motor 6, the brushless coreless motor 6 is a low-inertia, brushless and slotless motor, the running speed of the turbofan driven by the brushless coreless motor 6 is 2-6 ten thousand revolutions, the volute 1 includes an upper shell 11 and a lower shell 12, the upper shell 11 is provided with an air inlet 13, a flow channel 14 is disposed in the volute 1 along the circumferential direction, the tail end of the flow channel 14 is provided with an air outlet 17, an insert 23 is disposed in the impeller 2, the insert 23 is in interference connection with a shaft of the brushless coreless motor, the brushless coreless motor 6 drives the impeller 2 to rotate, the impeller 2 rotates to push air at the air inlet 13 to the flow channel 14 and blows from the air outlet 17, correspondingly, a low pressure area at the air inlet 13 and a high pressure area at the outlet of the impeller 2 and the flow passage 14 are formed.

Fig. 3 is a schematic cross-sectional view of a turbofan for a ventilator, fig. 4 is an enlarged view, fig. 5 is a schematic structural view of an upper housing 11, as shown in the drawings, the impeller 2 includes an upper cover 21 and an impeller main body 22, a plurality of blades are arranged between the upper cover 21 and the impeller main body 22, an outer wall of the upper cover 21 of the impeller 2 is arranged in parallel with a curved surface of an inner wall of the upper housing 11, an air seal plate 7 is further arranged on the lower housing 12, the air seal plate 7 is located below the impeller main body 22, a gap is arranged between the air seal plate 7 and the impeller main body 22, the gap is 0.5-1.3mm, when the gap is too small, the air seal plate 7 and the impeller main body 22 are easy to interfere and scrape, and when the gap is too large, the axial; the distance between the inner wall of the upper shell 11 and the outer wall of the upper cover 21 is 0.5-1.5mm, which means that the distances between the inner wall of the upper shell 11 and the outer wall of the upper cover 21 are equal and the design interval can be between 0.5-1.5mm, and the gap is too large, so that high-pressure gas at the outlet of the impeller is easy to leak to a low-pressure area of the inlet, high-pressure backflow is caused, energy loss is caused, pressure building at the outlet is not facilitated, meanwhile, a noise problem is caused, and the system efficiency is low. The gap between the inner wall of the upper shell 11 and the outer wall of the upper cover 21 is too small, the manufacturing control difficulty is high, the cost is high, and interference and shell wiping risks are easily caused.

The upper casing 11 and the lower casing 12 are provided with an annular straight air duct 16 in a matching manner between the flow channel 14 and the outer edge of the impeller 2, the inner wall of the outer end part of the upper casing 11 and the inner wall of the outer end part of the lower casing 12 are both provided with arc surfaces for forming the flow channel 14, the upper casing 11 and the lower casing 12 are both provided with annular surfaces 19 connected with the arc surfaces, the annular surfaces 19 on the upper casing 11 and the annular surfaces 19 on the lower casing 12 form the annular straight air duct 16 which is directly formed by the upper casing 11 and the lower casing 12 without adding additional parts, the annular straight air duct 16 is similar to a straight air duct along the radial direction of the impeller 2, air is sucked by the air inlet 13 under the action of the high-speed rotating impeller 2 driven by the hollow cup motor 7 and is guided into the impeller 2 along the extension section 15 of the air inlet 13, and the motor can be converted into kinetic energy and internal energy of the, after exiting the working impeller 2, it has a high air velocity, i.e. a high kinetic energy, which represents about 25% to 50% of the impeller work. Therefore, in order to effectively utilize the energy of the part, the kinetic energy of the part must be converted into pressure energy to achieve the purpose of increasing the air pressure, and the annular straight air duct 16 can help the high-speed gas to reduce the speed and smoothly transit to the flow passage 14, and better convert the kinetic energy into the required high-pressure gas.

As shown in fig. 6, the flow passage 14 has a cross-sectional area that increases linearly in the direction of the gas flow, and the cross-section increases as the flow passage approaches the outlet. When the gas enters different cross sections of the flow channel 14, the speed is different, and the linearly increased cross section area can ensure that the gas flows relatively uniformly in the flow channel 14. Further reducing the energy loss of the gas stream and better directing the mixed high velocity gas to circulate in the flow channel 14 in a relatively uniform manner.

As shown in fig. 4, the air inlet 13 is in a horn shape with an opening area gradually decreasing along the air inlet direction, and can have a larger air inlet 13 and uniformly guide air into the inlet of the impeller 2, so as to reduce the flow loss when the air enters, improve the system efficiency, and as a whole, the adjusting mechanism makes the minimum cross section of the air inlet 13 larger than the maximum cross section of the air outlet 17, thereby ensuring the air inlet amount.

In fig. 4, the high-speed gas at the outlet of the impeller 2 passes through the annular straight air duct 16, the gas further boosts the speed, the gas becomes high-pressure gas through the flow channel 14, the high-pressure gas at the position needs to enter a plurality of square or arc-shaped annular grooves 4 to reach a low-pressure inlet area, the circulation resistance is greatly increased, the gas at the high-pressure area at the flow channel 14 flows to the air inlet 13 of the low-pressure area, the possibility that the high-pressure gas flows to the low-pressure air inlet 13 is blocked, the energy loss is avoided, and the system efficiency is improved.

In fig. 4, the middle of the upper housing 11 is arranged parallel to the curved surface of the upper cover 21, the designed interval between the inner wall of the upper housing 11 and the outer wall of the upper cover 21 is 0.5-1.5mm, so as to ensure that the air passing duct 3 formed by matching the inner wall of the upper housing 11 and the outer wall of the upper cover 21 is uniform, 3 annular grooves 4 are arranged on the inner wall of the upper housing 11 corresponding to the upper cover 21, one or more annular grooves 4 can be arranged, the annular grooves 4 are annular with the rotation center of the impeller 2 as the center of circle, and can be distributed in the air duct when a plurality of annular grooves 4 are arranged, so that the flow blocking effect is better, the maximum depth of the annular grooves 4 is 1/3-2/3 wall thickness, the annular grooves 4 are too shallow, and; the annular groove 4 is too deep and is not beneficial to ensuring the structural strength, the opening of the annular groove 4 is 1-3 mm, the opening of the annular groove 4 is too small, the number of the annular grooves 4 is large, the process complexity is increased, the opening is too large, and the effect is poor. The dimensions of the annular groove 4 are mainly taken into account in the pressure difference between the high-pressure zone and the low-pressure zone.

Fig. 3 is a schematic sectional view of a turbofan for a ventilator, fig. 4 is an enlarged view, an extension section 15 opposite to the inner wall of an upper cover 21 is extended from the inner wall of an upper housing 11, the extension section 15 and the inner wall of the upper cover 21 are matched to form an intersecting air duct 5 communicated with a through air duct 3, the axial length of the intersecting air duct 5 is 1-4 mm, that is, the direction of the intersecting air duct 5 is changed from original approximate vertical to present approximate horizontal through the extension section 15 under the condition that an air inlet 13 is not changed, so that the influence of air flow intersection on each air flow is reduced, the flow from a high pressure area to a low pressure area is further reduced, and the air intake efficiency is guaranteed. The length of the relative part of the extension section 15 and the inner wall of the upper cover 21 is more than 1-4 mm, the axial length of the intersection air duct 5 is 1-4 mm, and the axial length is too small to form a stable air outlet direction; too big to stablize the air-out direction benefit not big, and increased the risk of interfering with the impeller blade in impeller 2 to be equipped with flow resistance groove 18 in upper housing 11 inner wall and extension 15 junction, further reduce air velocity, better prevent high pressure region gas to low pressure region flow, be favorable to better guarantee turbine efficiency.

Through the structural changes of the annular straight air duct 16, the flow channel 14 and the intersection air duct 5, the kinetic energy is better converted into the required high-pressure air through the annular straight air duct 16, the air outlet direction of the intersection air duct 5 is changed, the influence of air flow intersection on each air flow intersection is reduced, the flow resistance is increased to a certain degree, and the flow resistance is greatly increased by matching with the annular groove 4 in the air duct 3, so that the pressure is greatly reduced, a large-degree pressure difference cannot be formed, and further the air flow is difficult to form, the pressure loss of the outlet of the impeller 2 is reduced, the outlet pressure of the impeller 2 is improved, the pressure of a high pressure area is ensured, in addition, the air flow direction and the flow stability of the air flow of the air inlet 13 are ensured, namely, through the structural changes of the annular straight air duct 16, the flow channel 14, further reducing heat generation and improving system reliability.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims

1. The utility model provides a turbofan for breathing machine, includes brushless coreless motor (6), volute (1) and sets up impeller (2) in volute (1), volute (1) including last casing (11) and lower casing (12), last casing (11) be equipped with air intake (13), volute (1) in be equipped with runner (14), its characterized in that along circumference: the upper shell (11) and the lower shell (12) are provided with an annular straight air channel (16) in a matching manner, the annular straight air channel (16) is positioned between the flow channel (14) and the outer edge of the impeller (2), the annular straight air channel (16) is communicated with the flow channel (14), the impeller (2) comprises an upper cover (21), the inner wall of the upper shell (11) is matched with the outer wall of the upper cover (21) to form an air passing channel (3), the inner wall of the upper shell (11) is arranged in parallel with the curved surface of the outer wall of the upper cover (21), and the distance between the inner wall of the upper shell (11) and the outer wall of the upper cover (21) is 0.5-1.5 mm; the inner wall of the upper shell (11) is provided with at least one annular groove (4) relative to the upper cover (21), and the annular groove (4) is annular by taking the rotating center of the impeller (2) as the circle center; an extension section (15) opposite to the inner wall of the upper cover (21) extends from the inner wall of the upper shell (11), and the extension section (15) is matched with the inner wall of the upper cover (21) to form an intersection air duct (5) communicated with the air passing duct (3);

when the gas turbine works, gas is sucked from the air inlet (13) under the action of the high-speed rotating impeller (2) driven by the brushless coreless motor (6), and is guided into the impeller (2) along the extension section (15) of the air inlet (13), the motor energy is converted into the kinetic energy and the internal energy of the gas through the high-speed rotating impeller (2), the gas has high air velocity after coming out of the working impeller (2), namely, high kinetic energy, and the gas can help the high-speed gas to reduce the speed and smoothly transit to the flow channel (14) through the annular straight air channel (16), so that the kinetic energy is better converted into the required high-pressure gas; the high-pressure gas in the high-pressure gas inlet area can reach the low-pressure inlet area only by passing through a plurality of square or arc annular grooves (4) on the inner wall of the upper shell (11) relative to the upper cover (21), the extension section (15) can be used for controlling the flow of the high-pressure gas in the low-pressure inlet area without changing the air inlet (13), the direction of the intersection air duct (5) is changed from the original approximate vertical direction to the current approximate horizontal direction, thus reducing the influence of the air flow intersection on each air flow, being beneficial to further reducing the flow from a high pressure area to a low pressure area and being beneficial to ensuring the air inlet efficiency, the length of the relative part of the extension section (15) and the inner wall of the upper cover (21) is 1-4 mm, the axial length of the intersection air duct (5) is 1-4 mm, and a flow resistance groove (18) is arranged at the joint of the inner wall of the upper shell (11) and the extension section (15), so that the air flow speed is further reduced, the air in a high pressure area is better prevented from flowing to a low pressure area, and the turbine efficiency is better ensured.

2. The turbofan for a ventilator of claim 1 wherein: the section depth of the annular groove (4) is 1/3 wall thickness of the upper shell (11) -2/3 wall thickness of the upper shell (11), and the maximum opening width of the annular groove (4) is 1-3 mm.

3. The turbofan for a ventilator of claim 1 wherein: the annular grooves (4) are uniformly distributed in the air passing channel (3).

4. The turbofan for a ventilator of claim 1 wherein: the inner wall of the outer end part of the upper shell (11) and the inner wall of the outer end part of the lower shell (12) are respectively provided with an arc-shaped surface for forming a flow channel (14), the upper shell (11) and the lower shell (12) are respectively provided with an annular surface (19) connected with the arc-shaped surfaces, and the annular surface (19) on the upper shell (11) and the annular surface (19) on the lower shell (12) form an annular straight air channel (16).

5. The turbofan for a ventilator of claim 1 wherein: an air outlet (17) is formed in the tail end of the flow channel (14), and the cross section area of the flow channel (14) along the airflow direction is linearly increased.

6. The turbofan for a ventilator of claim 5 wherein: the air inlet (13) is in a horn shape with the opening area gradually reduced along the air inlet direction, and the minimum section of the air inlet (13) is larger than the maximum section of the air outlet (17).